<?php
interface Shape
{
    /** @return void */
    public function draw();
}

class Rectangle implements Shape
{
    public function draw()
    {
        echo "Rectangle\r\n";
    }
}

class Square implements Shape
{
    public function draw()
    {
        echo "Square\r\n";
    }
}

class Circle implements Shape
{
    public function draw()
    {
        echo "Circle\r\n";
    }
}
